Environmental Engineering Reference
In-Depth Information
incorporated. Nonengineered nanoparticles are unintentionally generated or natu-
rally produced, such as atmospheric nanoparticles created during combustion. For
nonengineered nanoparticles, physical properties play an important role as they
determine whether or not ill effects which will occur as a result of the presence of
these particles [
1
].
Examples
of industries with engineered and nonengineered nanoparticles:
• Some industries with engineered nanoparticles: chemical mechanical polishing,
pharmaceuticals, performance chemicals, cosmetics, bio detection and labeling,
food products, quantum dots, ceramics:
• Some industries with nonengineered particles: environmental monitoring con-
trolled environments, environmental detection.
Depending on the application of interest, nanoparticles may be known by a
number of alternative and trade-specific names, including particulate matter, aero-
sols, colloids, nanocomposites, nanopowders, and nanoceramics.
Nanoparticle characterization parameters include: hydrated surface analysis,
surface area and porosity, particle size distribution, solubility, adsorption potential,
zeta potential, aggregation, wettability, shape and size of interactive surface.
Nanoparticles are classified based on their dimensionality, morphology, composi-
tion, uniformity, and agglomeration. It is necessary to make a clear distinction
between nanostructured thin films or other fixed nanometer-scale objects (the
circuits within computer microprocessors) and free nanoparticles [
2
].
The motion of free nanoparticles is not constrained, and they can easily be
released into the environment leading to human exposure that may pose a serious
health risk. In contrast are the many objects containing nanostructured elements
that are firmly attached to a larger object, where the fixed nanoparticles should pose
no health risk when properly handled. An example of this is the material asbestos,
which is perfectly safe in its primary state (a type of solid rock), but is a significant
health hazard when is processed in such a way as to produce the carcinogenic
nanometer-scale fibrous particles that become airborne (aerosol) and are therefore
readily absorbed in the lungs [
3
].
13.2 Methods Used for the Characterization
of Nanoparticles
There are several techniques used to understand these characterization parameters
in nanoparticles: electron microscopy including TEM and SEM, atomic force
microscopy (AFM),
Nanoparticle tracking analysis
(
NTA
)
for tracking of the
Brownian motion
, dynamic light scattering (DLS), X-ray photoelectron spectros-
copy (XPS), powder X-ray diffraction (XRD), Fourier transform infrared spectros-
copy (FTIR), matrix-assisted laser desorption/ionization time-of-flight mass
